Abstract
The correlation between Down syndrome and Dandy-Walker syndrome is an exceptionally uncommon occurrence. To date, only four cases have been documented. All previously reported cases involved individuals under the age of 37 months, with prenatal or birth diagnoses. Additionally, most of these cases displayed a limited life expectancy and experienced poor developmental outcomes. In this report, we present the first-ever instance of an 11-year-old male patient, previously undiagnosed with Dandy-Walker syndrome, who presented with acute intracranial hypertension. Magnetic Resonance Imaging revealed an active hydrocephalus caused by a Dandy-Walker malformation. The patient's condition was effectively managed through the implementation of a ventriculo-cysto-peritoneal shunt. This case highlights the coexistence of Dandy-Walker syndrome and Down syndrome in an asymptomatic young patient. Furthermore, it demonstrates that active hydrocephalus in such cases can be successfully addressed through either endoscopic third ventriculostomy or ventriculo-cysto-peritoneal shunt procedures.